Shrines are cool during campaign and progression. Once in empowered monolith they often feel underwhelming.
It could be cool to have to option to transform them in “challenging shrines” for those who want extra challenge. It could be that while this option is activated (through an NPC) shrines give bonus to nearby enemies instead of you. In exchange for a reward like a loot explosion based on the number of empowered enemies.
Not that I’m totally against the purpose, although I don’t really want that specific change as I think shrines have a good purpose right now, but I am definitely not for the loot explosion part of the idea. We have enough loot explosion things going on right now already, especially with the lizards.
It would be kind like the events in D4. I think that it would be redundant, as we already have echoes where you need to seal a gate, which is basically the same thing as you propose. Bringing a challenge mode for shrines though is not a bad idea, just needs to be something different than a simple “kill monsters, get loot”. Maybe something like it summons monsters and you need to kill a number of them in a specific time frame to increase the echo reward. Or, if you do it in the time frame you go to a secret level where you fight an empowered boss and every drop is +1 LP. Or something